Currently, a bi-polarized broadband annular radiation unit is mainly formed by casting of zinc alloy. For example, Chinese Patent Application No.: CN101425626A filed by the present applicant Comba communication system (China) Ltd. and published on May 6, 2009 discloses bi-polarized broadband annular radiation unit. It includes the following parts: two pairs of orthogonally polarized dipoles for transmitting or receiving communication signals; and a balancer corresponding to each dipole for feeding power to the dipole in a balanced manner. Each dipole includes two unit arms symmetrically mounted on the respective balancer. Two arms are linearly symmetrical about the balancer. One end of each unit arm is secured onto the balancer, while the other end thereof is provided with a loading line extending vertically downwardly. In addition, a plurality of tuning bars with different cross section area from that of the unit arm is also provided. Though in terms of electric performance this kind of radiation unit brings contribution to the pertinent art, it suffers from large weight and high production cost due to formation by casting zinc alloy. In this context, radiation unit formed by sheet metal stamping has extensive application. It is a challenge for person of the art to apply this sheet metal stamping forming process and realize electrical performance of the radiation unit.